Effects of processing paths on the microstructure, mechanical properties and electrical conductivity of dilute Al-Zr-Sc alloy conductive wires

Understanding and clarifying the evolution of microstructure and performance of Al-Zr-Sc alloy wires during processing paths is a crucial issue in developing heat resistance conductors with high strength and high electrical conductivity (EC). In this study, the microstructure evolution and corresponding performance changes of Al-0.2Zr-0.06Sc alloy wires produced by three processing paths are investigated. Results indicate that aging treatment + hot extrusion + cold drawing processing path can produce the highest strength Al-Zr-Sc wires attributed to favorable interactions among precipitation strengthening of Al3(Zr,Sc) phases, grain boundary strengthening and dislocation strengthening. High EC is attained by the hot extrusion + aging treatment + cold drawing processing path, which reveals the importance of dynamic precipitation of Al3Sc phases during hot extrusion and further precipitation of solute atoms during ageing treatment for improving the EC. The processing path using hot extrusion + cold drawing + aging treatment achieves the highest EC of the Al-Zr-Sc wire, but the strength decreases significantly due to the loss of dislocation strengthening. Additionally, the pinning effect of Al3Sc and Al3(Zr,Sc) ensures good heat resistance of Al-Zr-Sc wires. These results provide guidance for the process design of Al-Zr-Sc wires with variable combinations of strength and EC.